Rotary panel cutter



June 28, 1966 H. o. HORNUNG 3,257,885

ROTARY PANEL CUTTER Filed June 19, 1964 2 Sheets-Sheet l A////SPiC/wPefssu 4425/4' C .n fllllllIl/l, 11111111 1111111111111111111111111111/l X//g/ Spec/nc P9535 z/PE ,425,0

June 28A, 1966 H. o. HoRNuNG 3,257,885

ROTARY PANEL CUTTER Filed June 19, 1964 2 Sheets-Sheet 2 @am mw P/m/ a5'Tlc'.E-

T1 .B- J4 55 5! @"5 0% United States Patent O 3,257,885 ROTARY PANELCUTTER Helmut O. Hornung, Scarsdale, N.Y., assiguor to F. L.

Smithe Machine Co., Inc., New York, NX., a corporation of New York FiledJune 19, 1964, Ser. No. 376,449

8 Claims. (Cl. Sil- 346) l This invention relates in general-to cuttingdevices, and methods of making said devices. More particularly theinvention relates to cutting knives for use in rotary panel cutters.

The present invention finds particularly utility in the manufacture ofenvelope blanks wherein blanks are advanced in succession intoassociation with a panel cutting mechanism for cutting away arectangular panel window, or in some instances a notch. The presentinvention is an improvement over devices of this character,particularlyin connection with the arrangement and method ofconstruction of the cutting knife associated with the panel cuttingmechanism.

In the past, one of the problems associated with uniformcuttingclearance knives used in rotary panel cutting devices was that theuneven distribution of cutting pressure applied over the blade contactarea causing premature dulling in the high pressure areas, or in thealternative incomplete serverance in the low pressure areas.

A novel cutter overcoming this problem is disclosed in U.S. LettersPatent, No. 3,106,121 having an assignee in Common with the presentapplication. In the foregoing patent the edges of the end portions ofthe knife are ground on a radius larger than the radius between the axisof rotation of the panel cutter and the edges of the side portions -ofthe blade. This grindingV technique effectively increases the cuttingclearance in the otherwise high pressure areas of the knife edge toequalize the pressure, and therefore wear, in that portion of the knifewith the pressure and wear in the other portions of the knife edge. Thepresent invention is an improvement overthat device, in that the desireduniform knifeedge cutting pressures. are obtained by a flexing of thecutting blade rather than as a result of a costly machining operation.

Accordingly,- it is an object of this invention to provide an improvedrotary panel cutter.

A further object of this invention is to provide a rotary panel cutterutilizing a panel cutting knife designed to flex during the cuttingoperation. l

Another object of this invention is to provide a rotary panel cutterutilizing a cutting knife having portions thereof preexed to a desiredradius.

A further object of this invention is to provide a flexible cuttingknife.

A further object of the invention is to provide a low cost method forthe production of cutters comparable in performance to cutter of theaforementioned U.S. Letters Patent.

Other objects and a fuller understanding of the invention may be had byreference to the following descripv tion and drawings, in which:

'l base by an adhesive 53 or other suitable means.

3,257,885 Patented June 28, 1966 ting edges have an effective radiuslarger than the radius from'the center of the mounting support roller tothe side cutting edges;

FIG. 5 is an enlarged partial cross-sectional view of the cutter ofFIGS. 3 and 4 taken on line 5 5 of FIG. 4;

FIG. 6 is a top plan view of a second embodiment of the invention FIG. 7is a cross-sectional view of the cutting knife of FIG. 6;

FIG. 8 is a view similar to FIG. 7 showing another embodiment of theinvention;

FIG. 9 is a view similar to FIGS. 7 and 8 showing still anotherembodiment of the invention; Y

FIG. l() is a greatly magnified diagrammatic view,l indicating therelative areas of low and high contact pressure between the cuttingknife and the anvil roller when the axis of the knife is parallel to theroller axis; and

FIG. 11 is a view similar to that shown in FIG. 10 indicating how therelative size of the cutting areas of the knife when mounting skew tothe axis of rotation of the anvil backing roller.

With reference to the drawings, the invention as illustrated as beingincorporated in a rotary panel cutter as shown generally in FIG. 1. Asillustrated, the rotary panel cutter includes a lower rotary panelcutting mechanism 20, and upper cooperating backing anvil roller 22.Envelope blanks 24 are fed in succession through the rotary panel cutterby means of a pair of conveyors 26 and 28. The conveyors 26 and 28 areprovided with upstanding aligning pins 30 and 32 which move behind andengage the notches in the trailing seal flap 34 of the envelope blank24, and accurately align each blank prior to its passage through thepanel cutting mechanism 20. The aligning pins 30 are arranged to feedthe blank 24, at a small angle offset from the direction of feed. Thepanel cutting mechanism 20 includes a central vacuum and pressurecontrolled cylinder 36 rotationally supported on a shaft 37. The shaftincludes a hollow central passageway 39 which communicates with a tube38 to a source.

of negative pressure or vacuum (not shown). The passageway 39 isselectively placed in communication with either tube 38 or 40 by a wellknown type of rotary to control the periods at which the centralpassageway 39 is subjected to either negative or positive pressure. Anelongated radial passage 44 places the passageway 39 in communicationwith a pair of small openings 46 in one of a pair of panel cuttingmounting shells 48. The semicircular shells 48 are aligned in positionover the cylinder 36 and clamped thereon by bolts 50.

One embodiment of the invention is shown in detail in FIGS. 2 to 6.Referring first to FIGS. 2, 3 and 6, the panel cutting knife includes acontinuous rectangular blade 52 which is positioned on a curved surfaceof a mounting base 54. The blade may be secured to the The blade 52 andbase 54 assembly, hereafter called the cutting knife is in turn `securedto the mounting shell 48 by means of bolts 56, 58 and 60, said cuttingknife being displaced from the surface of the mounting shell 48 by aspacer or shim 62. The shim 62 is rectangular in shape and of a lengthsubstantially less than that of the cutting knife. Theshim .62 iscentrally positioned along the length of the cutting knife so that theextremeends of the cutting knife overhang the ends of the shim 62. Bolt58 is seated in the center of the cutting knife and passes through theshim 62. Bolts 56 and 60 are seated in respective opposite ovcrhangingend portions of the cutting knife. The passageways 46 in the shell 48communicate with apertures 64 in the shim 62. The apertures 64communicate with a plurality of control apertures 66 which are eifectivetov placethe positive or negative pressure of passage-v 3 way 39 to theinterior confines of the panel cutting knife 52 (see FIG. 2).

FIG. 10 illustrates the relative pressures applied by the backing roller22 on the cutting knife during a typical panel cutting operation whenmounted with its axis par- Y allel to the shaft 37. It can be seen thatthe contact area of the side portions of the cutting knife issubstantially greater than that of the end portions of the cuttingknife, with a resulting low and high specific cutting pressuresrespectively. As pointed out in U.S. Patent, No. 3,106,- 121 andillustrated herein in FIG. l1, the cutting knife is usually mounted withits longitudinal axis slightly offset from the axis of the backingroller 22 to obtain a progressive sheared cut of the envelope blank 24.While offsetting the cutter in this way accomplishes a small degree ofbalancing of the cutting pressures between the side and end portions ofthe cutter, the longer side portions of the knife are neverthelesssubjected to much less force per unit area of contact (pressure) thanthe ends of the knife, and hence the side portions will not dull asrapidly as the end blade portions.

In accordance' with one embodiment of the present invention, this unevencutting pressure and wear of the blade edges is rectified by the use ofthe overhanging cutting knife, shim and bolt mounting arrangementdescribed above. Bolts 56 and 60 are stressed sufficiently to impart adownward deformation of the cutting knife so that the end portions ofthe blade edge have more clearance with the backing roller 22 during itsrotation than the relatively undeformed side portions of the blade havewith respect to backing roller 22. This relationship is illustrated inenlarged scale in FIGS. 4 and 5. The rotation radius is referenced tothe side portions of the blade 52 and compared with the new flexedradius of the blade 52 end portions. The increased clearance at the endedge portions result in a decrease in the force applied to the bladeedge contact area. This force reduction in the small contact area endportion of the knife is therefore effective to substantially equalizethe cutters pressure over all portions of the knifeedge.

Obviously due to the exing of the blade 52, during a panel cuttingoperation the side blade edges will penetrate deeper into the envelopeblank 24 that the end blade edges. Therefore the angle of liex impartedto the cutting knife by tightening bolts 56 and 60 and the subsequentreduction in end blade edge cutting force is limited by the thickness ofthe envelope blanks 24 to be cut, the proximity of the backing roller 22to the cutting blade and the minimum depth of penetration by the bladeedge that is necessary to completely sever a panel from the blank 24. Itshould be noted that cutting of the panel window from the blank materialis brought about by crushing and compressing the blank 24 between theedges of the cutting knife and the backing roller 22 to a point ofseparation through embrittlement of the bers by pressure alone. Apenetration of sixty percent or more of the thickness of the blank 24will be suicient to bring about this result. A small clearance, slightlyless than the thickness of the stock being cut, is therefore maintained`at all times between the knife and anvil roller 22.

In each of the embodiments a pair of annular rings 55 of resilientmaterial are located adjacent the ends o-f the cutter 52 and rotatetherewith. The rings S5 serve to tightly grip the envelop blank as theyare fed through the panel cutter thereby insuring cutting registrationaccuracy.

In FIG. 7 another embodiment of the invention is shown very similartoFIGS. 3-5. FIG. 7 differs therefrom only in that it includes an integralshim portion 62a formed on the underside of base 54a. In all otherrespects this embodiment is the same as FIGS. 3-5 will be readilyunderstood by those skilled in the art in view of the foregoingdesoription of FIGS. 3-5.

Another embodiment of the invention is illustrated in FIG. 8. Here amodified -mounting shell 68 is recessed at 69, so as to form a raisedsupport 72 or integral shim beneath the knife mounting block 70. Theblade 74 is secured to the upper surface of the mounting base 70 byadhesive and the blade 74 and mounting base 70 assembly (hereaftercalled the cutting knife) centrally positioned over the raised support72. In this embodiment the cutting knife is secured directly to the.raised support 72 by one or more bolts 76. Flexing of the cutting knifewith the resulting decrease in specific pressure at the end portion ofthe blade 74 is accomplished during the cutting operation by the naturalflexing of the overhanging end portions of the cutting knife whenpressure -is applied by the backing roller 78. The amount of cuttingknife exure in this embodiment is a function of the stiffness of thecantilevered end portions of the blade and the applied cutting force.Obviously, if the blade ends are made yieldable in this manner, thecutting pressures about the knife periphery will also be essentiallyequalized with the result that equal wear will be obtained.

'FIG. 9 shows another embodiment of the invention wherein a blade 78 ismounted on a ba-se 80 as in the previous embodiments. Here the cuttingknife assembly is mounted on a pad 82 made of rubber or other yieldablematerial.A The knife and pad 82 are secured to the mounting shell 84 bythree equally spaced and centered bolts 86. In this embodiment of theinvention, the concentrated application of force over the small cuttingarea of the blade ends when the blade comes in contact with the backingroller 88 causes a larger degree of exure in this area to also equalizethe cutting pressure about the blade periphery.

While various embodiments of the invention have been shown and describedin detail to illustrate the'application of the invention principles, itwill be understood that the invention may be embodied otherwise withoutdeparting from such principles.

What is claimed is:

1. A rotary cutter comprising rotary support means, knife means havingat least one side blade portion substantially parallel tothe axis ofrotation of said support means, and at least one end blade portionextending substantially transverse to the axis of rotation of saidsupport means, and means for rigidly mounting said knife means to saidsupport means, said mounting lmeans including means disposedintermediate to said knife means and said support means, saidintermediate means being of shorter length than said side blade portionand fastening means exterior of the ends of said intermediate means forreecting the end Iblade portion closer to the support means axis ofrotation than said side blade portion.

2. A rotary cutter according to claim 1 wherein said intermediate meansis a Shim.

3. A rotary cutter according to claim y1 wherein said knife meansincludes a mounting block and means to secure said blade portions tosaid mounting block.

4. Rotating apparatus for cutting panels from blanks of sheet materialcomprising a cylindrical mounting means having an axis of rotation,knife means having a substantially rectangular outline and including endblade portions extending generally transverse to the axis of rotation ofsaid cylindrical mounting means, elongated side blade portions extendinggenerally parallel to the axis of rotation of said cylindrical mountingmeans, a mounting block and means to secure said .blade portions to saidmounting block, intermediate means for rigidly mounting said knife meansto said cylindrical mounting means, said intermediate means beingdisposed intermediate to said knife means and said cylindrical mountingmeans and being of shorter length than said side blade portions,fastening means exterior to the ends of said intermediate means fordeecting the end blade portions closer to the cylindrical mounting meansaxis of rotation than said side blade portions, and an anvil rollercooperating with said knife means and arranged with its outer surfacespaced a predetermined distance therefrom.

5. Rotating apparatus according to claim 4 wherein said intermediatemeans is a shim.

6. A knife for use in'rotary panel cutters comprising blade means andsupporting base means, said blade means including at least one sideblade portion and at least one end blade portion extending substantiallytransve-rse to and in the plane of said blade portion, said supportingbase means having at least Ione pair of opposite surfaces, said blademeans extending upward from and affixed to one of lsaid surfaces, saidblade means terminating in a parallel to the `one of said surfaces, andthe opposite surface substantially undercut inwardly so as to leaveknife portions that can flex.

7. A knife for use in rotary panel cutters comprising a substantiallyrectangular blade and supporting rectangular base portion, said bladecooperating with one surface of said base portion and having cuttingedges substantially perpendicular to the plane of the one surface ofsaid base portion, with said cutting edges terminating in a planeparallel to said one surface of said base portion, said base portionhaving an opposite surface substantially overhangingA undercut inwardlyso as to leave overhanging knife porknife means, said knife meansincluding at least one side Iblade portion extending substantiallyparallel to the axis of rotation of said support means and at least oneend blade portion extending substantially transverse to the axis ofrotation of said support means, said mounting means includingintermediate ,me-ans being positioned intermediate to said kn-ife meansand said support means, said intermediate means being of shorter lengththan said side blade portion and fastening means interior to the ends ofsaid intermediate means for fastening said support means and said knifemeans to said mounting means, said intermediate means being suicientlyshort in length so as to allow the end blade por-tions of said knifemeans to deflect in the direction of the axis of rotation of saidsupport means due to the operating cutting pressures applied to said endportion of said knife means during operation.

References Cited by the Examiner UNITED STATES PATENTS 461,600 10/1891West 83-348 844,171 2/ 1907 McAuulty 83-348 1,978,136 10/1934 Kavle83-346 X 2,682,306 6/ 1954 Schriber 83--346 3,106,121 10/1963 Novick83-346 X WILLIAM W. DYER, JR., Primary Examiner.

J. M. MEISTER, Assistant Examiner.

1. A ROTARY CUTTER COMPRISING ROTARY SUPPORT MEANS, KNIFE MEANS HAVINGAT LEAST ONE SIDE BLADE PORTION SUBSTANTIALLY PARALLEL TO THE AXIS OFROTATION OF SAID SUPPORT MEANS, AND AT LEAST ONE END BLADE PORTIONEXTENDING SUBSTANTIALLY TRANSVERSE TO THE AXIS OF ROTATION OF SAIDSUPPORT MEANS, AND MEANS FOR RIGIDLY MOUNTING SAID KNIFE MEANS TO SAIDSUPPORT MEANS, SAID MOUNTING MEANS INCLUDING MEANS DISPOSED INTERMEDIATEMEANS BEING OF SHORTER SUPPORT MEANS, SAID INTERMEDIATE MEANS BEING OFSHORTER LENGTH THAN SAID SIDE BLADE PORTION AND FASTENING MEANS EXTERIOROF THE ENDS OF SAID INTERMEDIATE MEANS FOR REFLECTING THE END BLADEPORTION CLOSER TO THE SUPPORT MEANS AXIS OF ROTATION THAN SAID SIDEBLADE PORTION.